In a variety of document presentation systems such as printing systems, it is common to rasterize data to generate a bitmap representation of each sheetside image of the document by processing a sequence of data objects. The data objects are typically initially defined in a page description language or other suitable encoding and at some point prior to writing to a bitmap are represented as regions of rectangles of pixels. Typically, the sheetside image is then generated into a bitmap memory as a two dimensional matrix of pixels representing the intended document sheetside image, and subsequently compressed.
During sheetside processing, a calculation may be performed to determine an amount of overcoat ink to be provided on a page. Overcoat ink is used, for example, to protect ink from water and to provide a glossy finish. Such uses allow an overcoat ink plane to be generated from existing print data without requiring a user to generate additional data.
Overcoat planes are sometimes imaged at reduced resolutions, reduced bit depth, and at different intensities. Thus, the amount of overcoat ink needed is based on the amount of ink that needs overcoat. For example, 1200 dpi bitmaps of cyan, magenta, yellow and black (CMYK) data (e.g., 4 planes) currently require over 134 million algorithm calculations for data in an 8.5 by 11 inch page in order to determine overcoat amounts. Moreover, an additional four calculations must be averaged to determine a reduced resolution overcoat amount.
Accordingly, an efficient overcoat processing mechanism is desired.